Wireless communication system, centralized station, wireless communication method, and centralized control program

Abstract

A wireless communication system according to one embodiment of the present invention predicts, on the basis of a relevance degree of each user who uses a terminal, a traffic between the each terminal and each base station, selects a base station to connect on the basis of the traffic of each terminal, continuously collects the terminal position information relating to each terminal and a propagation loss information between each terminal and each base station, calculates a packet error rate of each selected base station on the basis of the collected terminal position information and propagation loss information, determines, on the basis of the calculated packet error rates, whether or not there is a terminal having a communication quality with respect to the base station less than a predetermined value, and when it is determined that there is a terminal having the communication quality less than the predetermined value, changes the base station to which the terminal is connected such that the communication quality of the connection of each terminal to the base station exceeds the predetermined value.

Description

Technical Field

[0001] The present invention relates to a wireless communication system, a central station, a wireless communication method, and a centralized control program.

Background Art

[0002] Conventionally, a technique for efficiently performing information communication by applying an algorithm similar to PageRank to the relevance of each user in an SNS (social networking service) and utilizing graph theory, big data analysis, etc. has been studied (for example, see Non-Patent Document 1).

[0003] For example, it has been studied to predict the traffic of each base station (existing in the cyber space) of a CPS (cyber physical system) and feed back the prediction to the real world for use as a guideline for base station selection of each user terminal.

[0004] Also, for example, regarding the power used in a wireless communication system, a method for improving efficiency using energy harvesting technology has been studied (for example, see Non-Patent Document 2).

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

[0006] However, conventionally, the actual wireless conditions of each terminal were not reflected, resulting in low accuracy in selecting the base station that each terminal should connect to, and sometimes failing to achieve the required communication quality.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a wireless communication system, a central station, a wireless communication method, and a central control program that enable each terminal to optimally select the base station to which it should connect from among multiple base stations while maintaining a predetermined communication quality. [Means for solving the problem]

[0008] A wireless communication system according to one embodiment of the present invention is a wireless communication system comprising a plurality of central stations that coordinately centrally control a plurality of base stations each capable of accommodating a plurality of terminals, wherein the central station comprises: a selection unit that predicts the traffic between each terminal and each base station based on the degree of relevance of each user using the terminal and selects the base station to which each terminal should connect based on the traffic of each terminal; a collection unit that continuously collects terminal location information indicating the location of each terminal and propagation loss information indicating the propagation loss between each terminal and each base station; a calculation unit that calculates the packet error rate of each base station selected by the selection unit based on the terminal location information and propagation loss information continuously collected by the collection unit; a determination unit that determines whether there is a terminal whose communication quality to the base station falls below a predetermined value based on the packet error rate calculated by the calculation unit; and a modification unit that, when the determination unit determines that there is a terminal whose communication quality to the base station falls below a predetermined value, changes the base station to which each terminal connects so that the communication quality to which each terminal connects exceeds a predetermined value.

[0009] Furthermore, a centralized control center according to one embodiment of the present invention is a centralized control center that centrally controls a plurality of base stations, each capable of accommodating a plurality of terminals, and is characterized by comprising: a selection unit that predicts the traffic between each terminal and each base station based on the degree of relevance of each user using the terminal and selects the base station to which each terminal should connect based on the traffic of each terminal; a collection unit that continuously collects terminal location information indicating the location of each terminal and propagation loss information indicating the propagation loss between each terminal and each base station; a calculation unit that calculates the packet error rate of each base station selected by the selection unit based on the terminal location information and propagation loss information continuously collected by the collection unit; a determination unit that determines whether there is a terminal whose communication quality to the base station falls below a predetermined value based on the packet error rate calculated by the calculation unit; and a modification unit that, when the determination unit determines that there is a terminal whose communication quality to the base station falls below a predetermined value, changes the base station to which each terminal connects so that the communication quality to which each terminal connects exceeds a predetermined value.

[0010] Furthermore, a wireless communication method according to one embodiment of the present invention is a wireless communication method in which a plurality of centralized stations cooperate to centrally control a plurality of base stations each capable of accommodating a plurality of terminals, and is characterized by including a selection step of predicting the traffic between each terminal and each of the base stations based on the degree of relevance of each user using the terminals and selecting the base station to which each terminal should connect based on the traffic of each terminal; a collection step of continuously collecting terminal location information indicating the location of each terminal and propagation loss information indicating the propagation loss between each terminal and each of the base stations, respectively; a calculation step of calculating the packet error rate of each of the base stations selected in the selection step based on the terminal location information and propagation loss information continuously collected in the collection step, respectively; a determination step of determining whether there are any terminals whose communication quality to the base station falls below a predetermined value based on the packet error rate calculated in the calculation step; and a modification step of changing the base station to which each terminal connects so that the communication quality to which each terminal connects exceeds a predetermined value if the determination step determines that there are terminals whose communication quality to the base station falls below a predetermined value. [Effects of the Invention]

[0011] According to the present invention, it is possible to optimize and select the base station that each terminal should connect to from among multiple base stations while maintaining a predetermined communication quality. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows an overview of a wireless communication system according to one embodiment. [Figure 2] This is a functional block diagram illustrating the functions of a device. [Figure 3] This is a functional block diagram illustrating the functions of a base station. [Figure 4] This is a functional block diagram illustrating the functions of a centralized control center. [Figure 5] This flowchart shows an example of how a centralized control station operates. [Figure 6]It is a diagram showing an example of the hardware configuration of a central station according to an embodiment.

Embodiment for Carrying Out the Invention

[0013] Hereinafter, a wireless communication system according to an embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing an overview of a wireless communication system 1 according to an embodiment. As shown in FIG. 1, a wireless communication system 1 according to an embodiment includes a plurality of central stations 4 that centrally control in cooperation with a plurality of base stations 3 each capable of accommodating a plurality of terminals 2.

[0014] The terminal 2 is a wireless terminal that a user uses for wireless communication respectively. The base station 3 may be a reflector or the like that relays radio waves. The central station 4 is configured to centrally control a plurality of base stations 3 in cooperation with other central stations 4.

[0015] Next, the functions of the terminal 2, the base station 3, and the central station 4 will be specifically described with reference to FIGS. 2 to 4.

[0016] FIG. 2 is a functional block diagram illustrating the functions of the terminal 2. As shown in FIG. 2, the terminal 2 includes, for example, an antenna 20, an amplification unit 21, an AD conversion unit 22, a demodulation and decoding unit 23, an information bit detection unit 24, and a position information notification unit 25.

[0017] The amplification unit 21 amplifies the signal received via the antenna 20 and outputs it to the AD conversion unit 22. Note that a conversion unit or the like for converting the frequency may be provided in front of the amplification unit 21.

[0018] The AD conversion unit 22 is an analog-to-digital conversion unit that converts the analog signal amplified by the amplification unit 21 into a digital signal.

[0019] The demodulation and decoding unit 23 demodulates the received data converted into a digital signal by the AD conversion unit 22, performs error correction decoding, and outputs it to the information bit detection unit 24.

[0020] The information bit detection unit 24 detects information bits from the signal input from the demodulation and decoding unit 23.

[0021] The position information notification unit 25 generates a notification signal for notifying the base station 3 of information indicating the position of its own station (the terminal 2) (terminal position information), and notifies the generated notification signal to the base station 3 via the antenna 20.

[0022] FIG. 3 is a functional block diagram illustrating the functions of the base station 3. As shown in FIG. 3, the base station 3 includes, for example, an antenna 30, an information bit generation unit 31, a modulation and encoding unit 32, a DA conversion unit 33, a radio conversion unit 34, a radio conversion unit 35, an AD conversion unit 36, a demodulation and decoding unit 37, an information bit detection unit 38, a power intensity detection unit 300, an obstacle information detection unit 302, and an environment information detection unit 304.

[0023] The information bit generation unit 31 generates information bits indicating data and the like to be transmitted to the terminal 2, and outputs them to the modulation and encoding unit 32.

[0024] The modulation and encoding unit 32 performs error correction encoding on the information bits generated by the information bit generation unit 31, then digitally modulates the data signal, and outputs it to the DA conversion unit 33.

[0025] The DA conversion unit 33 converts the data signal digitally modulated by the modulation and encoding unit 32 into an analog signal, and outputs it to the radio conversion unit 34.

[0026] The radio conversion unit 34 converts the analog signal converted by the DA conversion unit 33 into a predetermined radio signal, and transmits it via the antenna 30.

[0027] The radio conversion unit 35 converts the radio signal received via the antenna 30 into an analog signal of a predetermined frequency, and outputs it to the AD conversion unit 36.

[0028] The AD conversion unit 36 is an analog-to-digital conversion unit that converts the analog signal converted by the radio conversion unit 35 into a digital signal.

[0029] The demodulation and decoding unit 37 demodulates the received data that the AD conversion unit 36 ​​has converted into a digital signal, performs error correction decoding, and outputs it to the information bit detection unit 38.

[0030] The information bit detection unit 38 detects information bits from the signal input from the demodulation / decoding unit 37.

[0031] The power strength detection unit 300 detects the power strength of the signals received from each of the terminals 2 via the antenna 30 and notifies the central station 4. For example, the power strength detection unit 300 detects the gain of each multipath for each delay time. The power strength detection unit 300 may also have a function to detect the distance to the terminal 2 and the propagation loss between the terminals 2 and the terminals 2.

[0032] The obstacle information detection unit 302 is an image sensor, such as a CMOS sensor, that detects obstacles that may affect communication with terminal 2, and processes information indicating the detected obstacle to the central station 4. For example, the obstacle information detection unit 302 photographs objects located between each terminal 2.

[0033] The environmental information detection unit 304 detects the surrounding environment that may affect communication with terminal 2 and performs processing to notify the central station 4 of the environmental information indicating the detected surrounding environment.

[0034] The base station 3 is configured to have the function of transmitting to the central station 4, for example, the wireless quality status between it and terminal 2 (propagation loss, fading environment, shadowing), and terminal location information indicating the location of terminal 2 notified by terminal 2.

[0035] Figure 4 is a functional block diagram illustrating the functions of central station 4. Note that central station 4 is configured to have functions that allow it to cooperate with other central stations 4; therefore, other central stations 4 are also shown in a simplified form in Figure 4.

[0036] As shown in Figure 4, the central station 4 includes, for example, a collection unit 40, a big data processing unit 42, a linkage unit 44, a selection unit 46, and a modification unit 48.

[0037] The data collection unit 40 includes, for example, a location information collection unit 402, a power strength collection unit 404, an obstacle information collection unit 406, and an environmental information collection unit 408. It continuously collects terminal location information indicating the location of each terminal 2, and propagation loss information indicating the propagation loss between each terminal 2 and each base station 3, and outputs these to the big data processing unit 42.

[0038] For example, the location information collection unit 402 collects terminal location information indicating the location of each terminal 2 transmitted from the base station 3 and outputs it to the big data processing unit 42.

[0039] The power strength collection unit 404 collects power information indicating the strength of the received power from each of the terminals 2 transmitted from the base station 3, and outputs it to the big data processing unit 42.

[0040] The obstacle information collection unit 406 collects information indicating obstacles that affect communication with the terminal 2 transmitted from the base station 3, and outputs it to the big data processing unit 42.

[0041] The environmental information collection unit 408 collects environmental information indicating the surrounding environment that affects communication with the terminal 2 transmitted from the base station 3, and outputs it to the big data processing unit 42.

[0042] In other words, the collection unit 40 has the function of collecting terminal location information and propagation loss information calculated based on the power intensity detected by the power intensity detection unit 300 of the base station 3 and the objects photographed by the obstacle information detection unit 302.

[0043] The big data processing unit 42 generates the collection of big data from the CPS described above, and also controls the linking unit 44 and the modification unit 48 with the calculation unit 420 and the determination unit 422.

[0044] The calculation unit 420 calculates the packet error rate for each base station 3 that the selection unit 46 has selected, as described later, based on the terminal location information and propagation loss information that the collection unit 40 has continuously collected, and outputs it to the determination unit 422.

[0045] The determination unit 422 determines whether there is a terminal 2 whose communication quality to the base station 3 falls below a predetermined value, based on the packet error rate calculated by the calculation unit 420.

[0046] The collaboration unit 44 collaborates with other central stations 4 to share the results processed by the big data processing unit 42 with the other central stations 4, and also outputs them to the selection unit 46.

[0047] The selection unit 46 selects a base station 3 that terminal 2 should connect to based on the results processed by the big data processing unit 42, and outputs the processing result to the modification unit 48. For example, the selection unit 46 predicts the traffic between each terminal 2 and each base station 3 based on the relevance of each user using terminal 2, and selects a base station 3 to connect to based on the traffic of each terminal 2.

[0048] If the determination unit 422 determines that there is a terminal 2 whose communication quality to the base station 3 is below a predetermined value, the modification unit 48 controls the base station 3 to change the base station 3 to which each terminal 2 connects, so that the communication quality of each terminal 2 connecting to the base station 3 exceeds a predetermined value.

[0049] The central station 4 generates a collection of big data using terminal location information indicating the location of each terminal collected via the base station 3, and real data related to propagation loss (distance between terminal 2 and base station 3, shadowing due to obstacles, etc.). This data is then combined with the CPS big data mentioned above to accurately select the base station 3 that terminal 2 should connect to.

[0050] Next, an example of the operation of the central station 4 will be described. Figure 5 is a flowchart showing an example of the operation of the central station 4. As shown in Figure 5, for example, the central station 4 first collects actual data related to the terminal location information and propagation loss of each of the terminals 2 (S100).

[0051] Next, the central station 4 uses the CPS big data to calculate the wireless packet error rate for the selected base stations (S102).

[0052] Then, the central office 4 checks whether there are any terminals 2 whose traffic volume for each packet error rate has decreased and which fall below the required predetermined communication quality (S104).

[0053] The central station 4 determines whether all terminals meet the required predetermined communication quality (S106). If all terminals meet the communication quality (S106:Yes), the process ends; otherwise, it proceeds to process S108.

[0054] In the process of S108, the central station 4 performs the process of changing the connected base station for each terminal 2, and then returns to the process of S102.

[0055] Thus, the wireless communication system 1 according to one embodiment continuously collects terminal location information for each terminal 2 and propagation loss information indicating the propagation loss between each terminal 2 and each base station 3. If there is a terminal 2 whose communication quality to the base station 3 falls below a predetermined value, the system changes the base station 3 to which the terminal 2 is connected so that the communication quality exceeds the predetermined value. This makes it possible to optimize and select the base station 3 to which each terminal 2 should connect from among multiple base stations 3 while maintaining a predetermined communication quality.

[0056] Furthermore, each of the functions possessed by terminal 2, base station 3, and central station 4 may be partially or entirely comprised of hardware such as PLDs (Programmable Logic Devices) or FPGAs (Field Programmable Gate Arrays), or they may be comprised of programs executed by a processor such as a CPU.

[0057] For example, central station 4 can be implemented using a computer and a program, and the program can be recorded on a storage medium or provided via a network.

[0058] Figure 6 shows an example of the hardware configuration of a central station 4 according to one embodiment. As shown in Figure 6, the central station 4 has an input unit 50, an output unit 51, a communication unit 52, a CPU 53, a memory 54, and an HDD 55 connected via a bus 56, and is equipped with computer functions. The central station 4 is also configured to be able to input and output data to and from a computer-readable storage medium 57.

[0059] The input unit 50 is, for example, a keyboard and mouse. The output unit 51 is, for example, a display device such as a display. The input unit 50 and the output unit 51 may also be touch panels or the like.

[0060] The communication unit 52 is, for example, a communication interface for wireless communication.

[0061] The CPU 53 controls each component of the central control center 4 and performs predetermined processing. The memory 54 and HDD 55 store data, etc.

[0062] The storage medium 57 is capable of storing programs and the like that execute the functions of the central control station 4. Note that the architecture of the central control station 4 is not limited to the example shown in Figure 6. [Explanation of symbols]

[0063] 1... Wireless communication system, 2... Terminal, 3... Base station, 4... Central station, 20... Antenna, 21... Amplifier, 22... AD conversion unit, 23... Demodulation / decoding unit, 24... Information bit detection unit, 25... Location information notification unit, 30... Antenna, 31... Information bit generation unit, 32... Modulation coding unit, 33... DA conversion unit, 34... Wireless conversion unit, 35... Wireless conversion unit, 36... AD conversion unit, 37... Demodulation / decoding unit, 38... Information bit detection unit, 40... Collection unit, 42... Bit Data processing unit, 44...Linkage unit, 46...Selection unit, 48...Change unit, 50...Input unit, 51...Output unit, 52...Communication unit, 53...CPU, 54...Memory, 55...HDD, 56...Bus, 57...Storage medium, 300...Power intensity detection unit, 302...Obstacle information detection unit, 304...Environmental information detection unit, 402...Location information collection unit, 404...Power intensity collection unit, 406...Obstacle information collection unit, 408...Environmental information collection unit, 420...Calculation unit, 422...Determination unit

Claims

1. In a wireless communication system equipped with multiple central stations that coordinate and centrally control multiple base stations, each capable of accommodating multiple terminals, The aforementioned centralized station is A selection unit predicts the traffic between each terminal and each base station based on the relevance of each user using the terminal, and selects the base station to connect to based on the traffic of each terminal. A collection unit that continuously collects terminal location information indicating the location of each of the aforementioned terminals, and propagation loss information indicating the propagation loss between each of the aforementioned terminals and each of the aforementioned base stations, Based on the terminal location information and propagation loss information continuously collected by the collection unit, a calculation unit calculates the packet error rate for each of the base stations selected by the selection unit. A determination unit determines whether or not there is a terminal whose communication quality to the base station falls below a predetermined value, based on the packet error rate calculated by the calculation unit. If the determination unit determines that there is a terminal whose communication quality to the base station falls below a predetermined value, the modification unit changes the base station to which each terminal connects so that the communication quality of each terminal connecting to the base station exceeds the predetermined value. A wireless communication system characterized by having the following features.

2. The aforementioned base station is A power intensity detection unit that detects the power intensity received from each of the aforementioned terminals, An image sensor that captures an object located between each of the aforementioned terminals. It has, The aforementioned collection unit is The device collects terminal location information and propagation loss information calculated based on the power intensity detected by the power intensity detection unit and the image captured by the image sensor. The wireless communication system according to claim 1, characterized by the following:

3. In a centralized control center that coordinates and centrally controls multiple base stations, each capable of accommodating multiple terminals, A selection unit predicts the traffic between each terminal and each base station based on the relevance of each user using the terminal, and selects the base station to connect to based on the traffic of each terminal. A collection unit that continuously collects terminal location information indicating the location of each of the aforementioned terminals, and propagation loss information indicating the propagation loss between each of the aforementioned terminals and each of the aforementioned base stations, Based on the terminal location information and propagation loss information continuously collected by the collection unit, a calculation unit calculates the packet error rate for each of the base stations selected by the selection unit. A determination unit determines whether or not there is a terminal whose communication quality to the base station falls below a predetermined value, based on the packet error rate calculated by the calculation unit. If the determination unit determines that there is a terminal whose communication quality to the base station falls below a predetermined value, the modification unit changes the base station to which each terminal connects so that the communication quality of each terminal connecting to the base station exceeds the predetermined value. A centralized station characterized by having the following features.

4. The aforementioned base station is A power intensity detection unit that detects the power intensity received from each of the aforementioned terminals, An image sensor that captures an object located between each of the aforementioned terminals. It has, The aforementioned collection unit is The device collects terminal location information and propagation loss information calculated based on the power intensity detected by the power intensity detection unit and the image captured by the image sensor. A centralized station according to claim 3, characterized by the following:

5. In a wireless communication method in which multiple base stations, each capable of accommodating multiple terminals, are centrally controlled by multiple central stations working together, A selection step of predicting the traffic between each terminal and each base station based on the relevance of each user using the terminal, and selecting the base station to connect to based on the traffic of each terminal, A collection step of continuously collecting terminal location information indicating the location of each of the aforementioned terminals, and propagation loss information indicating the propagation loss between each of the aforementioned terminals and each of the aforementioned base stations, A calculation step, based on the terminal location information and propagation loss information collected continuously in the collection step, calculates the packet error rate for each of the base stations selected in the selection step, A determination step to determine whether there is a terminal whose communication quality to the base station falls below a predetermined value, based on the packet error rate calculated in the calculation step, If the determination step determines that there is a terminal whose communication quality to the base station falls below a predetermined value, the modification step changes the base station to which each terminal connects so that the communication quality of each terminal connecting to the base station exceeds a predetermined value. A wireless communication method characterized by including

6. The aforementioned base station is A power intensity detection unit that detects the power intensity received from each of the aforementioned terminals, An image sensor that captures an object located between each of the aforementioned terminals. It has, In the aforementioned collection process, The device collects terminal location information and propagation loss information calculated based on the power intensity detected by the power intensity detection unit and the image captured by the image sensor. The wireless communication method according to claim 5, characterized by the above.

7. A centralized control program for causing computers to function as parts of the centralized control station described in claim 3 or 4.

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